Pneumatic tire.



J. Cv BARKER. PNEUMATIC TIRE. APPLICATION FILED NOV. 13. 1916.

Patented Oct. 23,1917.

JOHN CHARLES BARKER, 01 LONDON, ENGLAND.

PNEUMATIG TIRE.

' eeann.

Specification of Letters Patent.

Application filed November 13, 1916. Serial No.181,126.

To all whom it may concern:

Be it known that I, Jorm CHARLES BAnKnn, a subject of the King of Great Britain, residing in London, England, have invented certain new and useful Improvements in Pneumatic Tires, of which the following is a specification.

. Thisinvention relates to the outer covers of pneumatic tires for the-wheels of vehicles of the kind wherein the tread of the tire is provided with a number of integrally formed-four sided truncated pyramidal pro-- jections arranged in parallel circumferem tial rows around the crown of the outer cover on either side of the central plane of the tire and in such a manner that those in one row are staggered with respect to those in an adjacent row, the inner sides of the projections being extended to the respectively opposite lateral portions of the cover. It consists in improvements having for their object to promote a better grip by the tire of a road surface, to localize the gripping to the parts of the tire where greater strength resides and there is least in tires of the above-menhood of the central p ane of the tire between the rows of projections, an arrangement which tends to render steerinfg more diflicult and leaves those sides o the pro ections next to and parallel with the central plane of the tire unsupported.

According to this invention, there is neither a continuous projecting strip along the crown nor is any space left between the rows of projections, but the inner edges of e tread surface 0 all the pro ections are all made to terminatein the said central plane, and the projections in one row are arranged to overlap and mer e into those of another row, the length of t e tread surface of each projection, measuned circumierentially in the direction of the line of e, either the projections have been- Patented0ct.23,191'? travel being eater than the correspond- I mgly measure length between the adjacent s1de edges of the tread surfaces of any'two neighboring projections of a row.

The invention will be described with ref erence to the accompanying drawing, in

which Figure 1 is a cross section through a tire having the improvements ap lied; Fig. 2 is a plan view of a portion oi.- tl e tire tread showing two rows of integral projections, and Fig. 3 is a side view of a portion of the tire represented in Fig. 1.

In the drawing, A denotes the outer cover of a tire'which is provided with an inextensible lining B, adapted toembrace the usual air tube which is not shown, and with a cushion piece C interposed between the lining B and under surface or backing of the tread portion of the outer cover A, the three members A, B and G being securely connected tog ther by vulcanizin or other suitable. ways. Two rows 0 projections at are to med on the outer cover,- one of said rows ope each side of the center D of the tread portion of the cover. These projections a have substantially rectangular tread surfaces, and, as shown in Fig. 2, the

projections a on one side of the center D of the tread portion of the cover are in staggored relation to those on the opposite side of said center. The former projections have i their inner sides or edges substantially in alinement with the corresponding sides or edges of the latter projections and with the center D of the tread portion of the cover. The ends of each of the projections a of the row on one side of the center D of the tread portion of the cover also overlap the ends of a pair of projections a of the row on the opposite side of said center. As clearly shown in Figs, 2 and 3, the sides a of the projections a which extend transversely with reference tothe tread portion of the cover taper in a manner to cause the bases of the projections to be larger than their tread faces with the consequence that each of the spaces 6 intervening between two pro ections of a row taper outwardly from the central plane, that is to say, the length of the space measured along circumferential lines parallel tothe central plane becomes shorter thefarther such lines are awayfrom the central plane. In this way the projections comprise great strength for all their sides taper, so that the l and base than at its tread surface. The nairowest part of a space between two adjacent projections of either row 13 between the outer extremities ofthe bases of the pro3ections, that is to say wherefthe' tread por tion merges into a side of the cover and where the tire has greater strength and 1s subject to least strains. The treadsurfaces 1 .B attaching of the projectionsa are preferablyflat as; shownin Fig.1;

to the inner .oronter surface of the outer cover the inextensible l niing B and interposedqbetween this lining and the tread portion A the :cushion piece C (whichmay' be a layered/soft rubber or equivalent material)-, strain istalzen 0d the "tread portion and any pressure transmitted by the inner tube absorbed. In'this way the treadportion of the tire not subject to any pressure from'the inflated airtube and can perform a gripping action on award surface with its natural 7 resiliency. The soft rubberlayer may coverjonly what corresponds to the tread portion of the lining,

, and need not extend down the side walls thereoii Thislayer also serves to protect edecti'vely the through water soaking througha damaged lining B from injury part on the outer face of the tire.

v as a furtherprecaution against creeping of the cushion'piece C and the forming of rocks on the under surfaceor backing E of the tread portion A, the outer surface of the backing a firm the sanie into practical sheet, I

clain1:-' v I 1. An outer cover for a pneumatlc wheeltire provided with a multiplicity of inv tegrally formed four-sided truncated pyramidal projections, arranged in two longitudinal rows around the tread portion of the cover and in staggered relation,the projections in each row being spaced apart and havingtread surfaces of rectangular configuration, the inner longitudinal edges of said surfaces each lying in the'central plane of the wheel and having a length, measured cireumferentially in the direction of the line of travel eater than the co'rres 011d.

ingly' measured length between adjacent.

transverse edgesot the tread surfaces of any two neghboring projections of a row.

2. An outerco'ver for a pneumatic Wheeltire provided with a multiplicity' of integrally formed four-sided truncated pyramidal projections arranged in two longitudinal rows around the tread portion of the cover and in staggered relation, the; projections in each row being spaced apart and having tread surfaces of rectan ular configuration, the inner, longitudina edges of said surfaces each lying in the central plane of the wheel and of such a length measured circumferentially in the direction of the line of travel that the inner. longitudinal edge of each of the tread surfaces of either row of projections overlap the inner longitudinal edges of the tread surfaces of two adjacent projections of the other row.

In testimony whereof i have signed my name to this specificationin the presence of two subscribing Witnesses. 1

JOHN C LES am Witnesses:

W. J. Snns'rnn, Josnrn Mariano. 

